Marine photovoltaic steel pipe and truss combined pile and construction method

Abstract

The invention provides an offshore photovoltaic steel pipe and truss combined pile which comprises a steel pipe of an upper pile section and a truss of a lower pile section, the truss can sink into seabed soil, and the transverse sectional area of the truss is larger than that of the steel pipe; a connecting section is connected between the bottom of the steel pipe and the top of the truss, the connecting section is provided with a closed section extending into the truss at the lower end of the steel pipe, the truss is provided with an extending section at the top end of a vertical rod of the truss, and lap joint parts which are connected and matched with each other are arranged between the closed section and the extending section. The steel pipes and the trusses are combined to form the combined pile, and the combined pile is of a steel pipe structure above the lowest water level (including the low tide level and the wave trough), so that wave force and ice pressure can be reduced; meanwhile, the truss structure below the lowest water level can further improve the bending resistance and horizontal bearing resistance of the pile foundation, and under the same material consumption, the bending resistance of the truss structure is improved by several times compared with a pile of a solid web structure.

Description

Technical Field

[0001] The invention relates to the technical field of offshore photovoltaic power generation, and in particular to a steel pipe and truss combined pile for offshore photovoltaic power generation and a construction method. Background Art

[0002] The pile foundation used in offshore photovoltaics has a large vertical distance from the top of the pile to the seabed soil surface due to water depth and wave factors, resulting in a large cantilever height and large horizontal load on the pile foundation, so the pile body generates a large bending moment near the seabed soil surface. Traditional offshore photovoltaic piles use prestressed concrete pipe piles or steel pipe piles. Although the unit price of prestressed concrete pipe piles is low, the pile body has weak bending resistance; while steel pipe piles have strong bending resistance, they use a large amount of steel and have a high unit price.

[0003] Piles used in offshore photovoltaics need to withstand much greater horizontal wave forces than onshore structures. Wave forces are related to the size and number of structures. The larger the size of the structure, the greater the wave force. The more wave-bearing structural parts there are, the greater the wave force. In addition, piles for offshore photovoltaics located in ice areas also need to withstand greater ice pressure, which is also related to the size and number of structures and is greater than wave forces. Therefore, for piles supporting offshore photovoltaics, it is necessary to minimize the effects of wave forces and ice pressure on the pile body. Summary of the invention

[0004] The first object of the present invention is to provide a composite pile with strong bending bearing capacity and reduced material consumption. To this end, the present invention adopts the following technical solutions:

[0005] A steel pipe and truss combination pile for offshore photovoltaics comprises a steel pipe of an upper pile section and a truss of a lower pile section, wherein the truss can be sunk into seabed soil, the truss is arranged below the lowest water level in the target operating sea area, and the steel pipe is arranged above the lowest water level, and the transverse cross-sectional area of ​​the truss is larger than the transverse cross-sectional area of ​​the steel pipe; a connecting section is arranged between the bottom of the steel pipe and the top of the truss, a closed section extending into the truss is arranged at the lower end of the steel pipe, and the truss is arranged at the top of the vertical pole of the truss, and a lap joint that is connected and cooperates with each other is arranged between the closed section and the extension section.

[0006] Furthermore: the truss is provided with diagonal bars between adjacent vertical poles.

[0007] Furthermore: the upper diameter of the closed section is the same as the diameter of the steel pipe, and the lower diameter is larger than the upper diameter, the upper and lower parts of the closed section have a smooth transition, and the extension section is inclined inwardly to the outside of the closed section.

[0008] Furthermore: a stiffening plate is connected between the outer surface of the extension section and the outer surface of the closed section.

[0009] Furthermore: a closed ring is provided at the top of the extension section, and the inner wall of the closed ring is connected to the outer surface of the closed section.

[0010] Furthermore: a closing plate is provided at the bottom of the closing section.

[0011] Furthermore: a horizontal baffle is provided in the area of ​​the truss below the seabed soil surface, and the horizontal baffle is connected between adjacent vertical poles.

[0012] Furthermore: the ends of the horizontal baffles in the vertical direction are connected to the transverse connecting rods on the trusses.

[0013] Furthermore: a ground-breaking plate is provided at the bottom of the truss, and the ground-breaking plate is arranged around the truss and connected to the vertical poles.

[0014] The second object of the present invention is to provide a construction method for smoothly sinking piles during pile sinking construction. To this end, the present invention adopts the following technical solutions:

[0015] The construction method of steel pipe and truss composite piles for offshore photovoltaics includes the following steps:

[0016] S1: constructing the steel pipes and trusses on land, assembling and connecting them, and transporting the assembled piles to the target operating sea area;

[0017] S2: Clamp a vibrating hammer on the top of the steel pipe, use the vibrating hammer to generate high-frequency vibration, and sink the truss into the soil after the seabed soil is liquefied or loosened;

[0018] S3: sinking piles until the truss vertically enters the target design depth;

[0019] S4: the vibrating hammer is released, the construction equipment is withdrawn, and the pile sinking work of the composite pile is completed.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention forms a composite pile by combining steel pipes and trusses. The steel pipe structure of the composite pile above the lowest water level (after taking into account the low tide level and the trough of the wave) can reduce the wave force and ice pressure; at the same time, the truss structure below the lowest water level can also improve the bending resistance and horizontal bearing capacity of the pile foundation. Moreover, under the same material usage, the bending resistance of the truss structure is several times higher than that of the prestressed concrete pipe pile or steel pipe pile of the solid structure. The present invention can not only smoothly transmit the impact force during pile sinking through the connecting section, but also reliably transmit the bending moment and horizontal force of the upper steel pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an elevation view of the overall structure of the steel pipe and truss composite pile of the present invention;

[0023] Figure 2 It is a plan view of the overall structure of the steel pipe and truss combined pile of the present invention;

[0024] Figure 3 is a plan view of a truss portion of the present invention;

[0025] Figure 4 It is an elevation view of the connection section of the steel pipe and the truss of the present invention;

[0026] Figure 5 It is a plan view of the connection section between the steel pipe and the truss of the present invention;

[0027] Figure 6 This is a vertical view of the earth-breaking toughness board of the present invention;

[0028] Figure 7 It is a plan view of the ground-breaking toughness plate of the present invention;

[0029] Figure 8 It is the elevation view of the horizontal baffle of the present invention;

[0030] Fig. 9 It is a plan view of the horizontal baffle of the present invention;

[0031] Fig.10 It is a diagram of the pile sinking process of the composite pile of the present invention.

[0032] The marks in the accompanying drawings are: 1-steel pipe, 2-seabed soil, 3-truss, 31-transverse connecting rod, 32-vertical upright, 33-diagonal rod, 34-extension section, 4-connecting section, 41-closed section, 42-closed plate, 43-stiffening plate, 431-first single-sided stiffening plate, 432-second single-sided stiffening plate, 44-closed ring, 5-soil-breaking tough plate, 51-vertical steel plate, 6-horizontal baffle, 61-vertical baffle, 7-vibration hammer, 8-hydraulic clamp. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0034] The combined pile provided in this embodiment has an upper pile section which is a 5-meter-long steel pipe 1, a lower pile section which is a 10-meter-long truss 3, and a middle pile section which is a 1-meter-long conical connecting section 4.

[0035] like Figure 1-10As shown, a steel pipe and truss combined pile for offshore photovoltaics comprises a steel pipe 1 of an upper pile section and a truss 3 of a lower pile section, wherein the truss 3 can be sunk into the seabed soil 2, and the truss 3 is arranged below the lowest water level of the target operating sea area, so that the pile body has a strong bending resistance, and since this place is no longer affected by waves and ice, the overall pile body is less affected by wave force and ice pressure; correspondingly, the steel pipe 1 is arranged above the lowest water level, and the bending moment here is not large, and the bending of the steel pipe can be easily satisfied; the lowest water level is the lowest water level after taking into account the low tide level and the trough of the wave; the transverse cross-sectional area of ​​the truss 3 is larger than the transverse cross-sectional area of ​​the steel pipe 1; a connecting section 4 is connected between the bottom of the steel pipe 1 and the top of the truss 3, and a closed section 41 extending into the truss 3 is arranged at the lower end of the steel pipe 1, and the truss 3 is provided with an extension section 34 at the top end of its vertical upright 32, and a mutually connected and matched overlap portion is arranged between the closed section 41 and the extension section 34.

[0036] It should be noted that the piles used for offshore photovoltaics are characterized by a large cantilever height at the top of the pile and a large horizontal load. Therefore, the bending moment of the pile body near the seabed soil surface is large, and the upward and downward bending moments are reduced. Traditional offshore photovoltaic piles use prestressed concrete pipe piles or steel pipe piles, which are solid-web structures. They either have weak bending resistance or large material consumption. The structure of truss 3 has a larger moment of inertia of the bending section than the solid-web structure, and its bending resistance is much higher than that of the solid-web structure. Therefore, with the same amount of material, the bending resistance of the truss 3 structure is several times higher than that of the solid-web structure.

[0037] In addition, offshore photovoltaic piles need to withstand much greater horizontal wave forces than onshore structures. Wave forces are related to the size and number of structures. The larger the size of the structure, the greater the wave force. The more wave-bearing structural parts there are, the greater the wave force. However, the steel pipe 1 of the thick-walled round steel pipe has a small diameter, a smooth appearance, and no redundant components. It is the cross-section type that is least affected by wave forces and ice pressure among all cross-section types.

[0038] like Figure 1 As shown, in this embodiment, the cross section of the truss 3 is a square, and vertical uprights 32 are arranged at the four corners of the projection in the vertical direction, and diagonal bars 33 and transverse connecting rods 31 are arranged between adjacent vertical uprights 32. The materials of the vertical uprights 32, transverse connecting rods 31 and diagonal bars 33 are all small-section round steel pipes. Among them, when the pile is under compression or tension, the contact and compression area between the pile and the soil is increased by the diagonal bars 33 arranged in an oblique direction; and due to the existence of a certain number of diagonal bars 33, the total compressive and tensile bearing capacity of the diagonal bars 33 is much greater than the compressive and tensile bearing capacity of the uprights, so that the combined pile has good compressive and tensile bearing performance.

[0039] like Figure 4As shown, the closed section 41 is in the shape of a cone. Specifically, the upper diameter of the closed section 41 is the same as the diameter of the steel pipe 1, and the lower diameter is larger than the upper diameter. The upper and lower parts of the closed section 41 are smoothly transitioned, and the extension section 34 is inwardly inclined to the outside of the closed section 41. In this embodiment, the closed section 41 is set at a slope between 1:6 and 1:10, and the inward slope of the extension section 34 is the same as the slope of the cone 41.

[0040] like Figure 4-5 As shown, specifically, a stiffening plate 43 is connected between the outer surface of the extension section 34 and the outer surface of the closed section 41. In this embodiment, the stiffening plate 43 includes a first single-sided stiffening plate 431 and a second single-sided stiffening plate 432. The first single-sided stiffening plate 431 and the second single-sided stiffening plate 432 form an angle of 45-60 degrees, which can effectively transmit torque. At the same time, due to the angle between the first single-sided stiffening plate 431 and the second single-sided stiffening plate 432, the tangential component force can effectively bear the torque.

[0041] like Figure 4 As shown, specifically, a closed ring 44 is provided at the top of the extension section 34, and all the extension sections 34 are connected together by the same closed ring 44, and the opening at the top of the extension section 34 is closed, and the inner wall of the closed ring 44 is connected to the outer surface of the closed section 41, and the top of the first single-sided stiffening plate 431 and the second single-sided stiffening plate 432 are closed. In this embodiment, the closed ring 44 and the inwardly inclined extension section 34 form an angle of about 45°.

[0042] A closing plate 42 is provided at the bottom of the closing section 41 to improve the corrosion resistance of the connecting section 4 in a seawater environment.

[0043] like Figure 1 and 8 -9, specifically, a horizontal baffle 6 is provided in the mud surface area of ​​the surface layer of the seabed soil 2 of the truss 3, and the horizontal baffle 6 includes a vertical baffle 61 connected between adjacent vertical uprights 32. The vertical baffle 61 surrounds the truss 3 in the area to increase the horizontal contact area between the truss 3 of the pile body and the seabed soil 2. When the pile body is deformed horizontally, the horizontal baffle 6 is acted upon by the reaction force of the soil, which can effectively reduce the horizontal deformation of the pile body near the mud surface of the seabed soil and improve the horizontal bearing capacity of the combined pile body.

[0044] In this embodiment, it should be noted that the soil on the surface of the seabed is often silty soil with low horizontal bearing capacity. When the pile is subjected to a large horizontal force, the horizontal deformation of the surface soil is too large, resulting in excessive horizontal deformation of the pile; therefore, the horizontal baffle 6 is set at a position about 1-1.5 times the width of the truss 3 below the mud surface of the seabed soil 2.

[0045] The top of the vertical baffle 61 in the vertical direction is connected to the transverse connecting rod 31 on the truss 3 , and the transverse connecting rod 31 is used to increase the horizontal stiffness of the horizontal baffle 6 and improve the horizontal bearing capacity of the horizontal baffle 6 .

[0046] like Figure 1 and 6 -7, specifically, in order to facilitate the pile sinking operation of the steel pipe 1 and truss 2 combined pile, a ground-breaking plate 5 is provided at the bottom of the truss 3, and the ground-breaking plate 5 is provided below the diagonal rod 33. The ground-breaking plate 5 includes vertical steel plates 51 arranged around the truss 3, and the vertical steel plates 51 are connected to the adjacent vertical uprights 32.

[0047] At the same time, the truss 3 uses a small-angle diagonal rod 33, that is, the angle between the diagonal rod 33 and the vertical rod 32 is controlled between 30-40 degrees, which can effectively reduce the reaction force of the soil, and at the same time improve the rigidity of the diagonal rod 33, ensuring that the diagonal rod 33 is smoothly inserted into the soil. Based on the above content, when sinking piles, the soil-breaking toughness plate 5 is first inserted into the soil. Since the soil-breaking toughness plate 5 itself is relatively thin, has a high height and high rigidity, it is easy to enter the soil. After the soil-breaking toughness plate 5 enters the soil, it breaks up the soil under the diagonal rod 33 under the action of vibration, so that the subsequent diagonal rod 33 can be smoothly inserted into the soil.

[0048] See also Figure 1-10 When constructing the combined piles of steel pipes and trusses, the specific steps are as follows:

[0049] S1: construct the required steel pipes 1 and trusses 3 on land, connect them together to form a composite pile, and transport the composite pile to the target operating sea area;

[0050] S2: A pile sinking method using a vibrating hammer 7 is used. The vibrating hammer 7 is clamped on the top of the steel pipe 1. The vibrating hammer 7 and the steel pipe 1 are clamped with a hydraulic clamp 8. The vibrating hammer 7 generates high-frequency vibrations. After the seabed soil 2 is liquefied or loosened, the truss 3 is sunk into the soil.

[0051] S3: Continue to use the vibrating hammer 7 to sink the pile, pay attention to the verticality of the pile body of the composite pile, and ensure that the truss 3 of the composite pile vertically enters the designed depth;

[0052] S4: The hydraulic clamp 8 and the vibrating hammer 7 are released, and the construction equipment is withdrawn, completing the pile sinking work of the single combined pile.

[0053] The above embodiment is only a preferred technical solution of the present invention. Those skilled in the art should understand that the technical solutions or parameters in the embodiments can be modified or replaced without departing from the principle and essence of the present invention, and all should be covered within the protection scope of the present invention.

Claims

1. Steel pipe and truss combined piles for offshore photovoltaics, characterized by: The invention comprises a steel pipe (1) of an upper pile section and a truss (3) of a lower pile section, wherein the truss (3) can be sunk into the seabed soil (2), the truss (3) is arranged below the lowest water level of the target operating sea area, the steel pipe (1) is arranged above the lowest water level, and the transverse cross-sectional area of ​​the truss (3) is larger than the transverse cross-sectional area of ​​the steel pipe (1); a connecting section (4) is connected between the bottom of the steel pipe (1) and the top of the truss (3), and a closed section (41) extending into the truss (3) is arranged at the lower end of the steel pipe (1); the truss (3) is provided with an extension section (34) at the top end of its vertical upright (32), and a mutually connected overlapping portion is arranged between the closed section (41) and the extension section (34).

2. The steel pipe and truss combined pile for offshore photovoltaic according to claim 1, characterized in that: The truss (3) is provided with diagonal bars (33) between adjacent vertical bars (32).

3. The steel pipe and truss combined pile for offshore photovoltaic according to claim 1, characterized in that: The upper diameter of the closed section (41) is the same as the diameter of the steel pipe (1), and the lower diameter is larger than the upper diameter. The upper and lower parts of the closed section (41) have a smooth transition, and the extension section (34) is inclined inwardly to the outside of the closed section (41).

4. The steel pipe and truss combined pile for offshore photovoltaics according to claim 1 or 3, characterized in that: A stiffening plate (43) is connected between the outer surface of the extension section (34) and the outer surface of the closed section (41).

5. The steel pipe and truss combined pile for offshore photovoltaic according to claim 1, characterized in that: A closed ring (44) is provided at the top of the extension section (34), and the inner wall of the closed ring (44) is connected to the outer surface of the closed section (41).

6. The steel pipe and truss combined pile for offshore photovoltaic according to claim 1, characterized in that: A closing plate (42) is provided at the bottom of the closing section (41).

7. The steel pipe and truss combined pile for offshore photovoltaics according to claim 1, characterized in that: The truss (3) is provided with a horizontal baffle (6) in the area below the mud surface of the seabed soil (2), and the horizontal baffle (6) is connected between adjacent vertical poles (32).

8. The steel pipe and truss combined pile for offshore photovoltaics according to claim 1, characterized in that: The end of the horizontal baffle (6) in the vertical direction is connected to the transverse connecting rod (31) on the truss (3).

9. The steel pipe and truss combined pile for offshore photovoltaics according to claim 2, characterized in that: A ground-breaking plate (5) is provided at the bottom of the truss (3); the ground-breaking plate (5) is arranged below the inclined rod (33) and is connected to the vertical stand (32).

10. A construction method for steel pipe and truss composite piles for offshore photovoltaics, characterized in that: The construction using the steel pipe and truss composite piles for offshore photovoltaics as described in any one of claims 1 to 9 comprises the following steps: S1: constructing the steel pipe (1) and the truss (3) on land, assembling and connecting them, and transporting the assembled pile to the target operating sea area; S2: clamping a vibrating hammer (7) on the top of the steel pipe (1), using the vibrating hammer (7) to generate high-frequency vibration, and sinking the truss (3) into the soil after the seabed soil (2) is liquefied or loosened; S3: sinking piles until the truss (3) vertically enters the target design depth; S4: the vibrating hammer (7) is released, the construction equipment is withdrawn, and the pile sinking work of the composite pile is completed.

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